The present invention relates to price display systems used in transaction establishments, and more specifically to an electronic price label (EPL) including a plurality of separately addressable displays.
EPL systems typically include a plurality of EPLs for each merchandise item in a store. EPLs typically display the price of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. A store may contain thousands of EPLs to display the prices of the merchandise items. The EPLs are coupled to a central server from where information about the EPLs is typically maintained in an EPL data file. Price information displayed by the EPLs is obtained from the PLU file.
EPLs today may be wired or wireless. Wireless EPLs may employ infrared or radio frequency (RF) transmitters. EPLs systems of the assignee of the present invention employ RF transmitters and modulated backscatter techniques. An EPL computer transmits polling signals to one or more EPLs. In order to respond to the poll, an EPL "reflects" the polling signal back to the EPL computer within a predetermined time interval of receiving the polling signal. A good analogy of the RF modulated backscatter acknowledgment signal is a mirror reflection. If two men face each other, one with a flashlight and the other with a mirror, the man with the mirror can send an acknowledgment to the man with the flashlight by reflecting the beam of light back to him. Similarly, the man with the mirror may indicate the opposite by not reflecting the light of the flashlight.
Modulated backscatter techniques are taught in U.S. Pat. No. 5,640,683, to Evans et al., entitled "Modulated Backscatter Wireless Communication System Having An Extended Range", issued Jun. 17, 1997. This patent is hereby incorporated by reference.
Typical EPLs have limited functionality. They have small displays, limited memory, and a simple communications protocol. Functionality is usually limited because cost is limited. Uses for EPLs exist that cannot be satisfied by current EPLs. For example, current EPLs do not readily function as marketing tools that attract and inform customers, because they are incapable of displaying long promotional messages. Also, current EPLs are too large to be located on shelves adjacent small merchandise items.
Therefore, it would be desirable to provide an EPL including a plurality of separately addressable displays to solve these and other problems.